Michigan gave up 12 plays of 40 yards or more last season, and five plays of 50 yards or more. On top of that, the 53 plays for 20 yards or more was the most the team has allowed since Greg Mattison returned to Ann Arbor in 2011.

That's not good.

Additionally, Michigan finished No. 66 nationally against the pass last year (231.3 yards allowed per game), the worst number recorded under Mattison and Hoke.

A lot of experience is back, but a lot also needs to change.

Here goes.

What we learned:
Well, at this point, the only thing that seems to be a certainty here is that junior Jarrod Wilson will be one of the team's starting safeties.

Everything else?

Well we'll have to see.

The breakout performer back here this spring was sophomore corner Jourdan Lewis. The 5-foot-11 Cass Tech product got his feet wet with a sprinkling of action a year ago, but mostly played behind Blake Countess and Ray Taylor. At times, Lewis was also behind classmate Channing Stribling as well.

But this spring, his development seemed to make a strong turn forward. He was the most aggressive defensive back in the spring game, and maybe the best defensive player overall -- picking off two passes and finding a way to be involved more often than not.

Lewis was also flagged for pass interference at least one time, which might look like a bad thing on the surface -- but at least it was a sign of aggression. After playing off in soft zones almost all throughout the 2013 season, Michigan is trying to force its corners to play with more physicality and aggression at the line of scrimmage. The Wolverines don't want to be a passive defense anymore, and in order for that to happen, the corners have to be strong on an island.

The big plays, though, will continue to be a concern. If Michigan's corners can't keep people in front of them on the edge (or at least run with receivers 1-on-1), then the Wolverines will have to go back to a zone mentality -- that means less blitzing, more bending without trying to break.

Taylor and Stribling also saw a good amount of time at corner opposite Lewis, and Countess spent most of the spring game inside at nickel -- which may ultimately be the best fit for him at this point, as he's a savvy corner with decent balls skills, but his 5-foot-10, 180-pound frame is just too small for most big-bodied targets.

The million dollar question here, of course, centers around prized freshman Jabrill Peppers.

Brady Hoke said earlier this spring that Peppers will likely start out by repping at nickel when he arrives for camp in August, but will also get a chance to crack the lineup at corner. He could also play safety, Hoke says. He's that versatile.

Peppers is 6-foot-1, 210 pounds. And he was one of the fastest high school players in America last season. He ran the 100-meter dash in 10.8 seconds, winning a New Jersey state title, and ran the 200 in just 21.13 seconds. He's been clocked at 4.43 seconds in the 40-yard dash.

So, he's big, he's athletic, he's strong and he can flat out fly. Physically, he may be more polished than any corner currently on Michigan's roster. Surely he'll find playing time somewhere. But where? And how much, how soon?

At safety opposite Wilson, sophomore Delano Hill has made his competition with Dymonte Thomas much more intense than anyone probably thought heading into spring ball. Thomas played more and more as the season wore on last season, and saw the most snaps of his year as a nickel in the Buffalo Wild Wings Bowl.

He was moved to safety this winter, and was expected to be the leader at that spot coming out of spring. But it was Hill who played almost exclusively with the first-string unit in the spring game. This could be a battle that continues through the end of spring camp. And, who knows, it could also feature Peppers.

Surprise name: Jourdan Lewis
Lewis, to me, was the defensive bright spot of the spring -- from what we got to see, anyway.

He, maybe more than any other corner on the roster at this point, seemed to embrace Michigan's mandate for more aggressive, more physical, more in-your-face play on the outside at corner. And that's going to be a necessity for next season. Lewis has track speed, he can run with anyone. But he's going to have to build on that frame.

Lewis is just 5-foot-10, 174 pounds. That three-digit number needs to be bigger, and it can't take away from his speed in the process.

This will be a big summer for Lewis, development-wise, but he's already taken a nice step forward this spring.

How will this shake out? Nick's best guess: Well, Peppers is going to play somewhere here.

He didn't turn down every other school in America to redshirt, or sit the bench. Especially in a secondary that is absolutely desperate for a ball-hawking corner on the outside.

Michigan may start Peppers out at nickel, but I'd be willing to be he ends up gradually moving more and more to the outside. Depending on how fast he picks up the speed of the game, maybe we could see him starting by the time Big Ten play rolls around? If that's the case, then the obvious move -- in my mind -- would be to push Countess to nickel (where he can still have a serious impact), and then let Lewis, Taylor and Stribling fight for that other spot.

In reality, I think the four corners that will be vying for outside spots will be Peppers, Lewis, Taylor and Stribling. It just makes more sense to play Countess inside at nickel, as most teams spread you out so much anyway.

As for the safety spots? Wilson is certainly going to win one of those jobs. The other? Thomas might be a better athlete, and he's taller (6-foot-2, 191) than Hill (6-foot, 205). But Hill turned enough heads to make this a battle during the spring.

I'd bet Thomas ultimately wins the job here, even if it takes a few weeks to nail down. Ultimately, in a perfect world, Michigan doesn't do much rotating back here.

You want to find four starters, and a solid nickel man, and let those five guys bond together and develop a chemistry.

And, above all else, you want to stay aggressive and stop the big plays.